The services offered by the Spectroscopy Support Facility (SSF) cover two distinct areas: 1) applications of nuclear magnetic resonance (NMR), circular dichroism, and fluorescence spectroscopy for studies of biomolecular structure and function, and 2) magnetic resonance microscopy (MRM) for In vivo imaging of small animals especially relevant to cancer research. The Facility houses two well equipped NMR instruments, a 600 MHz (14 Tesla) magnet with a Bruker DMX-600 console, a wide-bore 300 MHz (7 Tesla) magnet with a Bruker DRX-300 console, including a Biospec microimaging accessory. Facility personnel maintain and operate the spectrometers, perform NMR analytical and small-animal imaging services, and offer expert advice and technical support to users. The 600 MHz instrument is fully equipped for heteronuclear multidimensional NMR studies on the structure, dynamics and interactions of biological macromolecules. The 300 MHz instrument is well suited for multinuclear analysis of small molecules and studies of enzyme function involving isotopically-labeled ligands. Small-animal imaging on the 300 MHz instrument is of interest to investigators studying mouse models of cancer. MRM permits monitoring of tumor development, growth, perfusion, vascularization, and response to treatment. New capabilities for optical imaging are being implemented in order to study tumors expressing luminescent or fluorescent proteins in small-animal models. The Spectroscopy Support Facility was rated "Very Good to Excellent" at the last review. In 2003, the Facility was used by 18 peer-reviewed, funded investigators from 9 different Programs in all three Divisions. This represents an 80% increase over the number of users five years ago and addresses the previous concern that the Facility primarily served a small number of investigators in the Biomolecular Structure and Function Program. The broadened impact of the Facility is largely due to the implementation of small animal imaging, which made it possible to support cancer-related research Programs by eight additional users from all three Divisions. After the MR ilmaging services became fully operational, the usage of the 300 MHz instrument increased by two-fold. Over 99% of the total usage is by peer-reviewed, funded investigators. Data obtained with the help of the Facility have resulted in 27 publications in peer-reviewed journals over the past five years.